The present invention relates to a damping support for the suspension of an oscillating body on a support structure, and is particularly intended for reciprocating engines for motor vehicles.
The invention particularly concerns a damping support of the type comprising:
a tubular support body which is intended to be fixed to the support structure and is closed at one end so as to define a chamber containing a damping liquid, PA1 an attachment member which is intended to be fixed to the oscillating member and is connected coaxially to the other end of the tubular support body by means of an annular element of elastomeric material whose outer surface is fixed to the tubular support body and whose inner surface is fixed to the attachment member, and PA1 fluido-dynamic means for damping the oscillations of the attachment member relative to the tubular body, including a transverse disc member connected to the attachment member and immersed in the damping liquid.
Damping supports of the aforementioned type are suitable for damping large-amplitude, low-frequency oscillations, such as, for example, the oscillations of a motor vehicle engine under slow running conditions or in the event of sudden jolts to the vehicle caused by uneven ground. This type of support has disadvantages, however, in the case of low-amplitude, high-frequency vibrations, such as those which occur when the engine is running at high speeds of revolution, since it has a high dynamic rigidity which is further increased as the frequency of the vibrations increases whereby large pressure variations are transmitted as vibrations to the chassis of the motor vehicle to the detriment of the comfort of the ride.
A damping support of the type specified above is also known which further includes a transverse wall dividing the inner chamber into two chambers which communicate with each other through a restricted-passage duct for the damping liquid.
In this case, the support enables a low dynamic rigidity value to be obtained with high-frequency disturbances; in particular, the trace of the dynamic rigidity value as a function of the frequency of oscillation has its minimum in a certain frequency range at which the value of the dynamic rigidity is less than that of the static rigidity.